Hierarchical access scheme based on adjustable maximum transmission power level in wireless ad hoc networks

We consider access scheme with controllable power level in single channel for control message and data traffic. To increase the channel utilization, we propose a hierarchical access scheme based on adjustable maximum transmission power level. Hierarchical access scheme allows another communication of neighbor nodes within maximum power range. In our protocol operation, a node getting channel reservation sends data with minimum communication power level. Neighbors hearing channel reservation adopt the pre-reserving node as a parent and build subclusters. A neighbor can be given another transmission chance in virtual subcluster without disturbing on-going communication, which allows parallel communications in the maximum power range. We define a new message, NOTICE, and modify the conventional MAC header to support our proposed scheme. The proposed scheme allows parallel data transmission in single channel with avoiding asymmetric channel problem, and gives great increase of channel utilization compared with 802.11 DCF.